In such known grinding apparatus the outlet opening of the compressed-air motor communicates with the suction piping connection through a hose to the suction device for sucking off the grinding dust.
This has the disadvantage that the grinding apparatus must be designed for high performance, since it must not only absorb the amount of air which is needed for the suction of the grinding dust but also for the discharge air of the compressed-air motor. It is disadvantageous in this solution, since the oil which is contained in the discharge air cakes the grinding dust together to form to a connected mass in the suction device and is very poor in permitting air to pass therethrough.
The present invention is to provide a further development of a grinding apparatus so that it can be used together with a suction device having a low output.
In the inventive grinding apparatus, the discharge air is collected and discharged separately, and the suction device needs to be designed only for the air flow which is necessary for sucking off of the grinding dust. The grinding dust also does not come into contact with the oil traces and thus does not cake together in the filter of the suction device. Thus this filter also does not need to be cleaned as often; a cleaning of the filter which becomes necessary is simpler, since the filter cake can easily be removed from it.
With a further development of the invention, a compact arrangement of the hoses which carry the compressed air and discharge air is obtained. Furthermore one obtains in a very simple manner the requirement of providing differently sized cross-sectional dimensions for the hoses, as it must be chosen in view of the volume increase of the flow medium created during the exhaust of the compressed air in the compressed air motor.
With a still further development of the invention, it is achieved on the one side, that the entire hose arrangement can be handled externally as one unit. It is thereby particularly advantageous that the suction hose, which conducts the sucked-off air or the air-dust mixture, be designed mechanically strong because of the underpressure existing in it and thus also can hold together the hoses which lie particularly well in it. Furthermore in this manner one obtains also the desired large cross section for the suction piping connection and the suction hose, as it is desired in view of an unreduced forwarding of the suction output of the suction device to the grinding apparatus.
A still further development of the invention is preferable in view of the simple handling of the grinding apparatus. In the known grinding apparatus, several hoses for the air supply and air exhaust of the grinding apparatus started out from the apparatus itself, which hoses were able to get caught on the edges and corners of the workpiece. A "hose salad" is now avoided with the invention.
With a still further development of the invention, a splitting up of the common hose arrangement into individual hoses which extend in different directions is obtained in a very simple manner.
In a grinding apparatus embodying the invention, a minimum number of hoses exist also behind the adapter. The discharge air of the motor is exhausted through the deadener at the adapter to the atmosphere, which does not interfere since the adapter can be a considerable distance away from the actual working place.
Of course, it is possible to also choose a different form for the adapter, thus for example it may be round or cylindrical, if other situations permit this to be necessary.
The further development of the invention permits the use of the same hose material for the suction hose between the grinding apparatus and the adapter and between the adapter and the suction device.
The further development of the invention is advantageous in view of the secure placement of the adapter on a base and in view of the moving and removing of various hoses by rotation.
In a grinding apparatus embodying the invention, only two hoses need to exist for the air supply and the air exhaust for the grinding apparatus. The direct mounting of the deadener in the discharge-air piping connection is particularly not disadvantageous for grinding apparatus having a low work performance, since the discharge air exits from the deadener practically completely relaxed and diffused.